60VA means wattage. You need to find a 60 or 80 watt transformer. You can always go a little higher on wattage but stay with in volt limits.

When the sheet says +/-25 it means find a tranformer that is rated 50 volts or 25-0-25. Also making a power supply for amplifiers like QK114 is very easy. You may want to get 4 or 6 amp diodes. It is best to double on everything when making power supplies.